url2newtab - type in the url and opens a new tab
tab clicking options
duplicate tab - self explanatory, including duplicating history and you can merge tabs
gmail notifier
super dragandgo
minit (drag+indicator) - drag a tab to another tab location
flst - can focus on the last tab viewed if the current one is closed

I would recommend Clone Window, so like IE, if you want, it will open a duplicate copy of your current window, rather than the homepage. There's also an option for doing the same thing for the current tab with this extension.